Original Article Obstet Gynecol Sci 2015;58(1):46-52 http://dx.doi.org/10.5468/ogs.2015.58.1.46 pISSN 2287-8572 · eISSN 2287-8580
The association between oxidative stress and bone mineral density according to menopausal status of Korean women Young Joo Lee, Ji Yun Hong, Seung Chul Kim, Jong Kil Joo, Yong Jin Na, Kyu Sup Lee Department of Obstetrics and Gynecology, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea
Objective The aim of this study is to investigate the association between oxidative stress and bone mineral density (BMD) according to menopausal status of Korean women. Methods A total of 2,232 women who visited to the health promotion center at Pusan National University Hospital between 2010 and 2014 were included in this cross-sectional study. Laboratory tests, such as uric acid, albumin, total bilirubin, which were evaluated as a natural antioxidants. Homocysteine also was evaluated as a factor associated with oxidative stress. Correlation analyses and partial correlation coefficient between BMD scores and laboratory parameters associated with oxidative stress according to menopausal status were performed with Pearson test. Results By correlation analysis, uric acid had only positive correlation with femur and lumbar BMD in premenopausal and postmenopausal group. But albumin and bilirubin, which were the other natural antioxidants, had no correlation with BMD except total bilirubin with femur BMD in postmenopausal group. Homocysteine had negative correlation with femur BMD in postmenopausal group. But there were different results in partial correlation coefficient adjusted by age and BMI. In premenopausal group, uric acid was still positive correlation with femur and lumbar BMD, whereas in postmenopausal group homocysteine had no correlation with femur BMD, total bilirubin and uric acid had no correlation with lumbar BMD. At the multiple logistic regressions, only age and menopause status, uric acid had correlation with BMD. Conclusion In this study, homocysteine had no correlation with BMD. But in natural antioxidant, uric acid had only positive correlation with BMD. Keywords: Bone density; Homocysteine; Menopause; Uric acid
Introduction Osteoporosis is an important health problem and a major predisposing factor for fracture. As the population aging, the prevalence of osteoporosis gets higher and the social burden increasing. So it has been an important subject to investigate the factors that influence the occurrence of osteoporosis. Some of them were modifiable factors such as smoking, alcohol consumption, low calcium intake and others were not modifiable factors such as aging, female gender, menopause [1-3]. Recently, oxidative stress or low circulating levels of antioxidants were proposed to be related with reduced bone mineral density (BMD) and caused osteoporosis by in vitro studies or animal
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studies [4-6]. Uric acid, bilirubin and albumin has been known as natural antioxidants. Actually, it has been reported that higher Received: 2014.5.26. Revised: 2014.8.11. Accepted: 2014.9.1. Corresponding author: Jong Kil Joo Department of Obstetrics and Gynecology, Pusan National University Hospital, Pusan National University School of Medicine, 179 Gudeokro, Seo-gu, Busan 602-739, Korea Tel: +82-51-240-7287 Fax: +82-51-248-2384 E-mail:
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Young Joo Lee, et al. Oxidative stress and BMD in Korean women
uric acid levels were linearly associated with higher lumbar spine BMD in perimenopausal and postmenopausal women. It might be due to the major role of uric acid in free radical scavenger activity [7]. Bilirubin suppressed oxidation and albumin was an important contributor to maintain total antioxidant status [8,9]. So, the antioxidant activity by these factors could be influence the BMD. On the contrary, homocysteine was a factor associated with oxidative stress in vivo [8,10]. But, the relationship between homocysteine and BMD is still unclear. Some studies reported that high homocysteine was related with increased bone turnover and fracture risk in elderly [11,12], but other studies didn’t [13,14]. Homocysteine level might be changed with endogenous sex steroids levels [15]. So, the change of homocysteine levels through the menopausal transition may have influence on the decrease of BMD or development of osteoporosis in postmenopausal women. The research for the relationship of natural antioxidants and BMD could confirm the influence of oxidative stress for development of osteoporosis and the natural antioxidants levels could be used as variables predicting the occurrence of osteoporosis. The aim of this study is to investigate the association between oxidative stress and BMD according to menopausal status of Korean women
Materials and methods 1. Study population and anthropometric measurements A total of 2,232 women who visited to the health promotion center at Pusan National University Hospital between 2010 and 2014 were included in this cross-sectional study. Demographic data were collected at the time of the visit. Information on menstrual history, lifestyle, disease history and medication history were obtained with self-report questionnaires and interviews with healthcare providers. Body weight and height were
measured when standing barefoot, up to 0.1 kg and 0.1 cm, respectively. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared. We conducted our research based on self-report questionnaires. We included patients prepared our self-report questionnaires without exception and excluded patients who had been taking a steroid medicine for asthma, arthritis, rheumatic disease, which could affect BMD and also excluded patients taking a bisphosphonate and selective estrogen-receptor modulator. But we included 390 hypertension patients, 95 diabetes patients, 353 hyperlipidemia patient, all these patients had been taking a medication, 115 smokers. We also included patients had been taking a vitamin D or calcium medication on our research. 2. Blood sampling and laboratory analysis Bloods were obtained from antecubital vein from all subjects between 8:30 and 10:00 a.m., after fasting for at least eight hours. Laboratory tests were evaluated, which consisted of uric acid, albumin, total bilirubin as a natural antioxidants and homocysteine as a factor associated with oxidative stress. BMD was measured by dual-energy X-ray absorptiometry (Hologic QDR-4500A, Bedford, MA, USA) at the lumbar spine (L1–L4), femur neck and femur total. BMD results were classified into three groups according to World Health Organization criteria (normal BMD, T-score ≥-1; osteropenia, -2.5< T-score
